Metal reduction process

ABSTRACT

An improved metal reduction process permits the efficient production of metals from reducible metal compounds by means of a reducing metal. The reducible metal compound and a stoichiometric amount of a reducing metal are introduced into a sealed reaction zone and heated to a temperature which is above the melting point of the reducing metal but below the temperature at which a reduction reaction between the reducible metal compound and the molten reducing metal will proceed spontaneously. In this temperature range, a reduction reaction is initiated between the reducible metal compound and the molten reducing metal by suddenly disrupting the surface of the molten reducing metal and allowing the reduction reaction to continue to completion.

United States Patent [191 Hurd Apr. 2, 1974 METAL REDUCTION PROCESSPrimary Examiner-Reuben Epstein [76] Inventor: Frank Hum, PO BOX 14, LeAttorney, Agent, or FzrmJones and Lockwood Sueur, Minn. 56058 [22]Filed: July 26, 1972 [57] ABSTRACT [21] Appl. No.: 275,257 An improvedmetal reduction process permits the efficient production of metals fromreducible metal comi Apphcatmn Data pounds by means of a reducing metal.The reducible [63] Commuanon-m-pa" 0f 833373 June 16, metal compound anda stoichiometric amount ofa rel969 abandoned' ducing metal areintroduced into a sealed reaction zone and heated to a temperature whichis above the {521 US. 75/845, 75/62, 75/84.1 R melting point oftthereducing meta] buttbelow the [51] Int. Cl. G22b 5/00, C22b 53/00temperature at which a reduction reaction between [58] Field of Search75/845, 62, 84.1 the reducible metal Compound and the molten reduc ingmetal will proceed spontaneously. in this tempera- [56] References C'tedture range, a reduction reaction is initiated between NITED STAT PATENTSthe reducible metal compound and the molten reduc- 2,843,477 7/1958Booge 75/845 ing metal by suddenly disrupting the surface of the2,963,362 12/1960 Muller et al.. 75/845 molten reducing metal andallowing the reduction re- 2,986,462 5/l96l Wright 74/845 action tocontinue to completion. 2,994,603 8/1961 Greenberg et al. 75/845 15Claims, 7 Drawing Figures METAL REDUCTION PROCESS CROSS REFERENCE TORELATED APPLICATION This application is a continuation-in-part of Ser.No. 833,378, filed June 16, 1969, now abandoned.

BACKGROUND OF THE INVENTION Numerous processes exist for the productionof metals and their alloys from reducible compounds of such metals. Forexample, titanium and other metals have been produced by processes whichinvolve reacting the corresponding metal halide, such as titaniumtetrachloride, with a reducing metal, such as magnesium, under reducingconditions. One existing procedure involves the trickling or other slowaddition of titanium tetrachlorideonto or across the top of a large massof tetrachloride onto magnesium in an effort to reduce the titanium fromits polyvalent form to its zero valence state, while producing magnesiumchloride as a by-product.

Further, experiments have been conducted by others in which a reduciblemetal compound and a reducing metal have been placed in a small closedreaction vessel and heated therein, without agitation, to a thermalinitiation temperature at which a reduction reaction between thereducible metal compound and the molten reducing metal will proceedspontaneously. However, when such a spontaneous reaction is initiated,the reaction proceeds so rapidly that enormous internal pressures aredeveloped within the closed reaction vessels. Accordingly, it isuncommon for large bulk reactions to be performed by the foregoingprocedure on a commercial scale. Instead, industry has relied onprocedural modifications involving the slow and incremental addition ofone or both of the reactants to a closed reaction zone which ismaintained at or near atmospheric pressure. However, this modifiedprocedure also has its disadvantages since the modification involves thetime-consuming steps of selecting, monitoring, and changing the rates ofaddition of the reactants to the closed reaction zone in order tocontrol the temperature of the reaction zone. As an example of thetimeconsuming nature of the modified procedure, according to onereported procedure used by the U.S. Bureau of Mines, titaniumtetrachloride was slowly fed into a reaction vessel above the surface ofa large bath of molten magnesium which was enclosed within the reactionvessel. 2 hours after the titanium tetrachloride addition was begun,only 40 percent of the total amount of the reactant had been introducedinto the reaction vessel.

SUMMARY OF THE INVENTION The present invention relates to an improvedmetal reduction process which permits the efficient production of ametal from its reducible metal compound by reacting substantially all ofthe reducible metal compound simultaneously with substantially all of areducing metal in a closed reaction zone without encountering theextremely high pressure conditions or timeconsuming steps common to theexisting procedures discussed above.

Briefly described, the process of this invention includes the followingsteps. A reducible metal compound and a reducing metal are introducedinto a reaction zone, without any pre-mixing of these reactants, in

amounts usually not more than 10 percent excess of either reactant overthe stoichiometric requirements for the complete reduction of the metalcompound to the zero valence state of the metal. After the reaction zoneis sealed, the reactants are heated therein, without any significantagitation of the reactants, from a tempera ture below the melting pointof the reducing metal to a temperature which is above the melting pointof the reducing metal but below the thermal initiation tem perature atwhich the reduction reaction will proceed spontaneously. After thereactants are brought to within the foregoing temperature range, areduction reaction is initiated between reducible metal compound and thereducing metal by suddenly disrupting the surface of the molten reducingmetal and allowing this reaction to continue spontaneously andexothermically to thereby produce the zero valence state of the reducedmetal. Subsequently, the reduced metal is withdrawn from the reactionzone.

An important feature of the present invention is that the reactants aremaintained at a temperature significantly below the thermal initiationtemperature before the reduction reaction is initiated by the suddendisruption of the surface of the molten reducing metal. The thermalinitiation temperature in this case is defined as the temperature towhich the reactants must be heated at rest in a sealed reaction vesselto cause the reaction to proceed spontaneously without disrupting thesurface of the molten reducing metal and then to continue to react tocompletion without the benefit of externally supplied heat or agitation.

Another important feature of the present invention, is that after thereduction reaction is completed, the product, the zero valence state ofthe reduced metal, is substantially separated from the by-product saltand can be easily recovered from the reaction vessel.

THE DRAWINGS FIG. 1 is a side elevation of an apparatus, including areaction vessel, which can be used in the practice of this invention ona laboratory scale.

FIG. 2 is a cross-sectional view of the reaction vessel shown in FIG. 1.This view is taken along the lines 22 in the direction of the arrows inFIG. 1.

DETAILED DESCRIPTION THE REDUCIBLE METAL COMPOUND The process of thepresent invention is applicable to any metal compound which can bereduced with a mo]- ten reducing metal. Such reducible compounds includethe halides, oxides and sulfides of titanium, zirconium, hafnium,vanadium, niobiom, tantalum, silicon, germanium, tin, lead, thorium,uranium, boron, beryllium, and the like. Among the various compounds ofthese metals, the metal salts of the common inorganic acids arepreferred. The metal halides are particularly preferred, especially thehalides of the metals found in groups IVA, IVB, VA, VB, VIA, and VIB ofthe Periodic Chart. To a somewhat lesser extent, the halides of metalsof groups IIIA, IIIB and the actinoid Series can be used to advantage inthe present process.

Illustrative reducible metal compounds are TiCl TiBr TiF.,, ZrCl.,, BeClSnCl NbCl VCl TaCl UCl.,, UF ThCl Fe O Nb O C00 and M08 Reducible metalcompounds of the transition metals are very useful in this invention. Ofthe transition metals, titanium and zirconium are preferred. The presentinvention is usually well suited for the production of titanium fromtitanium tetrachloride and zirconium from zirconium tetrachloride.

Further, alloys of the various metals discussed above can be produced bythe process of the present invention. For example, a titanium-tin alloycan be formed by reacting a reducible metal compound of titanium, suchas TiCl and a reducible metal compound of tin, such as SnCl in thepresence of a suitable reducing metal, such as sodium, within theconditions of the present method.

The metals which can be used as reducing agents in the present inventioninclude any metal which is capable of reducing the selected reduciblemetal compound. As is known in the art, metals which will reduce certaincompounds will not reduce all compounds. However, the selection of asuitable reducing metal is within the skill of the art once thereducible metal compound is identified or selected.

The reducing metals used in the practice of this invention can beselected from the group consisting of alkali metals, such as lithium,sodium, and potassium; the alkaline earth metals, such as magnesium,barium, and calcium; aluminum; and the rare earth misch metals.

Preferred reducing metals include sodium, magnesium, potassium, lithium,barium, calcium and mixtures thereof. Sodium, mixtures of sodium withbarium, sodium with calcium and sodium with potassium are particularlyuseful as reducing metals for reducible metal halide compounds, such asTiCl BeCl ZrCl VCl NbCl TiB TiF and UF Although aluminum is not a goodreducing metal for producing metals from reducible metal halidecompounds, it does function satisfactorily as a reducing metal for otherreducible metal compounds, such as Fe o Cr O TiO ZnO and mixtures of FeOand TiO Selection of Suitable Reactants In many instances, the selectionof the reducible metal compound is limited by the availability incommercial quantities of reducible compounds of the selected metal. Forexample, titanium tetrachloride is commercially available or can beprepared from commercially available raw materials. Accordingly,titanium tetrachloride is one primary source of titanium metal.

The selection of a suitable reducing metal is within the skill of theart when aided by this disclosure. Factors to be considered in selectinga reducing metal for use in the process of this invention include thefollowmg:

l. The ability of the reducing metal to react with the reducible metalcompound under the anticipated conditions of use.

2. The melting point and boiling point of the reducing metal compared tothose of the reducible metal compound.

3. The cost and commercial availability of the reducing metal.

4. The relationship between the melting point of the reducing metal andthe thermal initiation temperature for the reduction reaction for theselected combination of reducible metal compound and reducing metal.

5. The type of by-products produced during the reduction process.

As previously indicated, particularly effective combinations ofreducible metal compound and reducing metal are the combination oftitanium tetrachloride and sodium metal, and the combination ofzirconium tetrachloride and sodium metal.

Relative Amounts of the Reactants When possible, the relative amounts ofreducing metal and reducible metal compound which are used in thepractice of this invention should be substantially stoichiometric.Ordinarily it is not necessary to use any significant excess of eitherof the reactants, and the use of substantial excesses, for example, over25 percent excess of either reactant, should be avoided. Ordinarily, theprocess of this invention requires less than 10 percent excess of eitherreactant, and desirably less than 5 percent excess of either reactant.Preferably, less than 1 percent excess of either reactant is mostdesirable. The Temperature The temperature at which the reaction of thepresent invention is initiated, by the sudden disruption of the surfaceof the molten reducing metal, is below the boiling point of the reducingmetal and can range from the melting point of the reducing metal up towithin about 50 C. of the thermal initiation temperature for thereduction reaction.

By thermal initiation temperature, I mean the temperature to which thereactants must be heated at rest in a sealed reaction vessel to causethe reactants to react spontaneously without disrupting the surface ofthe molten reducing metal and then to continue to react to completionwithout the benefit of externally supplied heat or agitation.

By contrast, initiation of the process of the present invention ischaracteristically induced at temperatures significantly below thethermal initiation temperature. Thus, if one heats the reactants to aninitiation temperature as taught herein (i.e., significantly below thethermal initiation temperature), and either does not mechanicallyinitiate the reduction reaction by intentionally disrupting orproliferating the surface and body of the molten metal, or inadequatelymanipulates the reactants in mechanically initiating the reductionreaction, little or no reaction will occur and the reaction will notproceed to completion.

Desirably, the temperature at which the process of the present inventionis initiated will be the minimum required to achieve an acceptable rateof reaction when the surface of the molten reducing metal is sharplydisrupted in the presence of the reducible metal compound. In thepresent invention the preferred temperature of initiation is more thanC. and usually more than 200 C. below the thermal initiationtemperature.

Frequently, a combination of reducible metal compound and reducing metalcan be selected so that there is a broad temperature range, for example,several hundred centigrade degrees, over which the reaction could beinduced or mechanically initiated. However, once initiated, the reducingreaction is exothermic and the temperature will rise above thecalculated thermal initiation temperature. With this in mind, it isadvantageous in the present invention to select the lowest initiationtemperature that meets many or all of the following objectives:

a. The temperature should provide an acceptable rate of reaction whenthe reaction is initiated;

b. The temperature should be at or above the boiling point of thereducible metal compound; and

c. The temperature should be high enough to cause the exothermictemperature reached during the reaction to be sufficient enough tomaintain the reduced metal and the by-product salt above their meltingpoints.

When using magnesium or sodium as the reducing metal, and using titaniumtetrachloride as the reducible metal compound, the thermal initiationtemperature for the reduction reaction is ordinarily in excess of 600 C.and thermally initiated reduction processes, such as the Kroll process,are typically carried out within the temperature range of from 700850 C.By contrast, the present process can be carried out at temperatures aslow as the melting point of sodium (about 98 C.). A very usefulinitiation temperature for the present process, using sodium metal asthe reducing metal and titanium tetrachloride as the reducible metalcompound, is from I20-400 C.

Initiating the Reaction The reduction process of the present inventionis initiated by disrupting the surface of the molten reducing metalafter it has been heated to the temperature previously indicated. Thiscan be accomplished by abruptly shaking or jarring the reaction vesselor zone, by rapid agitation of the reactants, or by any other meanswhich produces a sudden material change in the shape or area of thesurface of the molten metal which is exposed to or in contact with thetitanium tetrachloride.

Disrupting the surface of the molten metal results in a proliferation ordispersion of freshly exposed reducing metal into initmate contact withthe reducible metal compound. this disruption or proliferation of themolten metal serves to initiate the reduction reaction in the presentinvention. Another way of viewing this phenomenon is to consider thatthe thermal initiation temperature under quiescent conditions, that isthe thermal initiation temperature of the prior art, is higher than theinitiation temperature under conditions wherein molten reducing metal isbeing dispersed or proliferated as in the present invention.

Although a variety of means can be used to disrupt or proliferate themolten reducing metal, vertical agitation, that is agitation in adirection perpendicular to the surface of the molten metal, is much moreeffective than, for example, side to side shaking or rotary mixing invertically oriented cylindrical reaction vessels. Thus, the direction ofagitation can be important and should ordinarily be performed in thedirection or manner which results in the best or most efficientproliferation of the molten reducing metal. With cylindrical reactionvessels, agitation in the direction of the axis is preferred. Forexample, end-on-end mixing against the flattened ends of the reactionvessel is particularly beneficial.

Once initiated, heat is produced by the reduction process and desirablythe external heat should be removed from the reactor and, if necessary,cooling means should be provided for controlling the temperature withinthe reaction zone.

Reaction Vessel and Related Equipment The reaction vessel can take anyof a variety of shapes. Apparatus suitable for practicing this inventionon a laboratory scale is shown in the drawings.

In FIG. 11, a reaction pot or vessel, generally designated by thenumeral 1, is attached to a supporting arm 2 which is bolted to anextension arm 3. Extension arm 3 extends over a block 4 which serves asfulcrum. Block 4 rests on floor 5.

Reaction vessel 1 comprises a cylindrical body 6, the upper end of whichis closed. The open end of cylindri cal body 6 is provided with anoutwardly extending annular flange 7 which is provided with means, suchas bolts, for fastening gasket 8 and cover 9 to cylindrical body 6.Reaction vessel I is further adapted for attachment to supporting arm 2.

The details of construction of reaction vessel 1 are shown more clearlyin FIG. 2.

In operation, the reaction vessel which in FIG. 1 is disassembled andevacuated and/or purged with an inert gas, such as argon, as is known inthe art. Then, while operating within an inert atmosphere, the reducingmetal and the reducible metal compound, in stoi chiometric proportions,are placed in cylindrical shell 6 in quantities sufficient to, forexample, fill approximately 40-80 percent of the volume of reactionvessel 1. The reaction vessel is then sealed by attaching the cover 9 tothe cylindrical body 6 with suitable bolts and a copper gasket 8.Reaction vessel 1 is then attached to supporting arm 2. The contents ofthe reaction vessel 1 are then heated to the desired temperature. Thisheating can be accomplished by various means including the use of aheating mantle encircling the body of reaction vessel 1 and/or by meansof a heater placed between floor 5 and supporting arm 2 immediatelybelow reaction vessel 1. After the desired temperature has beenobtained, heating is discontinued.

Next, the reduction reaction is initiated by quickly or sharplydisrupting the surface of the molten metal within reaction vessel 1.Although various means can be used to accomplish this purpose, aconvenient laboratory method is to suddenly depress or rotate extensionarm 3 about fulcrum 4 one or more times in rapid succession to providesharp vertical agitation.

While not wishing to be bound by any theory, it has been observed that acoating forms on the surface of the molten metal which is in contactwith the reducible metal compound and it is believed that this coatingor surface layer inhibits the reduction reaction until either thetemperature is raised high enough to thermally initiate the reaction,for example, by causing the molten metal to boil, or until the surfaceof the molten metal is sharply disrupted to thereby expose fresh moltenmetal. By initiating the reaction in the latter manner, such as bymechanically disrupting the surface of the molten metal, the reactioncan be started at a lower temperature and the enormous pressuresassociated with the prior art processes can be avoided. In the case ofreducible compounds of polyvalent metals, this may be the result of ashift in the reaction mechanism and- /or the reaction kinetics.

For example, once the reaction between titanium tetrachloride and sodiumis initiated by disrputing or proliferating the surface of the moltensodium, the reaction proceeds spontaneously. The reaction is exothermicand it has been observed that some or all of the reaction vessel 1 willtake on a red glow as the reaction proceeds. With small reaction vesselsup to 10 liter capacity, the reduction reaction can be allowed toproceed without external heat and without external cooling means. Afterthe reaction has completed, the reaction vessel and its contents canthen be permitted to cool to room temperature. The reaction vessel isthen detached from supporting arm 2 and cover 9 is removed. The interiorof the reaction vessel 1 will typically appear as shown in FIG. 2. Atthe bottom of reaction vessel 1 will be a disc or plaque 10 of titaniummetal. Above this will be a salt deposit 11 of sodium chloride. The topand side walls of cylindrical body 6 will be covered with a thin layerof material 12 which may be salt, excess sodium metal, and smallparticles or nodules of titanium which adhere to the reactor walls.

It has been found that although small particles of titanium have beenfound along the upper side walls and top of reaction vessel 1, there arevery few readily identifiable titanium particles within salt block 11.Excess sodium, when present, tends to deposit along the top wall orupper end of reaction vessel 1. For some reason, the titanium nodules orparticles which are sometimes found along the upper walls of reactionvessel 1, within deposit layer 12 are more ductile or softer than thetitanium disc or plug 10.

The present invention is further illustrated by the following specificexamples which evidence the applica' bility of the present invention toreducible metal compounds of titanium, zirconium, hafnium uranium,vanadium, niobium, thorium, beryllium, and molybdenum. As can be seenfrom the following examples, the process of the present invention isparticularly useful in the production of titanium, zirconium, hafnium,uranium, vanadium, niobium and thorium from reducible halide compoundsof these metals.

Unless otherwise indicated in the following examples, all parts andpercentages are by weight.

EXAMPLE 1 This example illustrates the improved reduction process ofthis invention using titanium tetrachloride as the reducible metalcompound and sodium as the reducing metal. It further illustrates howother metals (such as copper) can be placed in the reaction zone to bemelted and combined with or alloyed with the metal being produced by thereduction process.

The apparatus used in this example was of the type shown in FIG. I. Thereaction vessel was constructed from a section of a mild steel casingapproximately 3/8 inch thick. A 3/8 inch steel plate was welded acrossone end of the casing and an annular 3/4 inch steel flange was welded tothe opposite end of the casing to provide a reaction vessel of theconfiguration shown in FIGS. 1 and 2. The interior dimensions of thisreaction vessel were 6 inches in diameter and 8 inches high. A steelcover was made from 3/4 inch steel. 510 grams of sodium metal from asodium brick and 615 ml. of titanium tetrachloride were placed in thereaction vessel after first inverting it. A solid copper gasket (0.05inches thick) was placed over the flange and the cover plate was thenbolted to the flange using eight equally spaced /8 inch bolts. Thegasket was disc-shaped and was within the inside bolt circle.Consequently, much of the gasket was exposed to the contents of thereaction vessel.

Next, the sealed reaction vessel was heated in an oven for approximately2-3 hours until the temperature of the reaction vessel reachedapproximately 175 C.

The reaction vessel was then removed from the oven and immediatelyattached to a steel supporting arm. A wooden plank approximately feetlong was used as the extension arm. A block of wood nominally 4 inchesby 6 inches in cross sections was used as the fulcrum. The surface ofthe molten sodium was sharply disrupted by rapidly depressing the leftend of extension arm 3 as shown in FIG. 1 several times in rapidsuccession. The movement of the extension arm about the fulcrum wassufficient to cause the reaction vessel to rise approximately 6-8 inchesfrom the floor before falling back to the floor. This sharp agitationwas sufficient to initiate the reduction process.

Shortly after the reaction was initiated, the lower one-third of thereaction vessel became red. The vessel was set level and the reactionwas immediate and complete. After completion of the reaction, thereaction vessel was permitted to cool to room temperature. The reactionvessel was then removed from its supporting arm, inverted and opened.The contents of the reaction vessel were substantially identical to thatshown in FIG. 2.

A well consolidated lump of titanium metal and copper, as hereinafterexplained, weighing approximately 128 grams was obtained from the bottomof the reaction vessel. See FIG. 2, element 10. 791 grams of sodiumchloride crystals, containing no discernible particulate metal wereremoved from the reactor. See element 11 of FIG. 2. The outside of thereactor was pounded with a mallet to loosen material which had adheredto the inner walls of the reaction vessel. In this manner, 526 grams ofa mixture of small nodules and particles of ductile metal admixed withsodium chloride particles, were recovered. Of this amount, 197 gramswere titanium. Very little material remained within the reaction vessel.

Essentially no un-reacted sodium or titanium tetrachloride was found inthe reaction vessel.

Total metal recovery (as the lump and as small nodules) was in excess ofthe theoretical yield of titanium metal. Subsequent examination of thereaction vessel and of the titanium plaque revealed that a portion ofthe copper gasket which was exposed to the interior of the reactionvessel had melted during the reaction and was co-mingled or alloyed withthe titanium metal that was recovered from the cover of the reactionvessel.

The estimated temperature range at which the reaction would be initiatedby only heating, the thermal initiation temperature, is from 500 to 600C. The reac- Lt sl is E am e was tiatcda a g it l In this example,titanium metal was again produced from titanium tetrachloride usingsodium as the reducing metal.

The experimental apparatus of Example 1 was modified to the extent thatthe cover 9 was welded to the body of the reaction vessel after it wasloaded with the reactants.

In Example 2, the reaction vessel was loaded with l. 8 Kg. of sodium inthe form oftwo commercial two pound sodium bricks each measuringapproximately 8 inches by 2% inches by 2% inches. A stoichiometricamount (2,190 ml.) of titanium tetrachloride was then added and thereaction vessel was sealed. It was then attached to the supporting arm.The contents of the reaction vessel were heated over a period of severalhours until the temperature as measured externally along the top of thereaction vessel had reached approximately 180 C. Heating wasaccomplished by lifting the reaction vessel from the floor sufficientlyhigh to permit an electric heating element to be placed on the floorunderneath the reaction vessel. An electric heating element or mantlewas also placed around the reaction vessel. A cover of insulating boardwas then placed over the reaction vessel to prevent massive heat losses.When the temperature reached approximately 180 C., the heating elementsand insulated cover were removed. The contents of the reaction vesselwere then agitated by rapidly raising the reaction vessel about 8 inchesfrom the floor (using the extension arm for this purpose) and allowingit to drop under its own weight. This procedure was repeated three timesin rapid succession, that is, in less than seconds. The reaction betweenthe molten sodium and the titanium tetrachloride was thereby initiatedand immediately the lower one-half of the reaction vessel turned red.The reaction was immediate and complete. After the completion of thereaction, the reaction vessel was allowed to cool to room temperature asthe reaction subsided. After the reaction vessel had cooled tosubstantially room temperature, the reaction vessel was opened and thecontents appeared substantially as shown in FIG. 2.

425 grams of titanium metal was recovered in a consolidated mass orlump. See element 10 of FIG. 2. This represents approximately 44 percentof the theoretical yield of titanium metal. In addition to thisconsolidated mass of titanium metal, nodules of titanium metal werefound along the upper side walls of the reaction vessel and along thetop of the reaction vessel. The combined weight of these nodules and thelump was in excess of 95 percent of the theoretical yield of titanium.

The nodules of titanium metal attached loosely to the wall weresubstantially softer than the consolidated mass of titanium found in thebottom of the reaction vessel. No discernible particles of titaniummetal were found in the crystalline mass of sodium chloride which waslocated immediately above the lump of titanium. See element 111 of FIG.2.

The estimated temperature range at which this reaction would beinitiated by only heating, the thermal initiation temperature, is from500 to 600 C. The reac' tion in this Example was initiated at about 180C.

EXAMPLE 3 In this Example, titanium metal was produced from titaniumtetrachloride using a mixture of sodium and calcium as the reducingmetal.

In this embodiment 100 ml. of titanium tetrachloride, 61 grams of sodiumand 21.5 grams of calcium were placed in the 300 ml. reactor. Thereactor was sealed and heated in an oil bath to an oil bath temperatureof 230 C. Upon shaking of the reactor at this temperature, a veryvigorous reaction occurred. After the completion of the reaction 41.56grams of titanium were recovered for a yield of 95.4 percent. Thereduction reaction of this Example was initiated at 230 C., whereas thethermal initiation temperature for this reaction lies in the range from500 to 600 C.

EXAMPLE 4 In this Example, titanium metal was produced from titaniumtetrachloride using a mixture of sodium and barium as the reducingmetal.

In this embodiment of the present invention, 100 ml. of titaniumtetrachloride, 45 grams of sodium, and 125 grams of barium were placedin the 300 ml. reactor.

The reactor was then shaken for about 60 seconds, which shaking produceda very vigorous reaction. After the completion of the reaction, 43.08grams of titanium were recovered for a yield of 98.8 percent.

The reduction reaction of this Example was initiated at 230 C., whereasthe thermal initiation temperature for this reaction lies in the rangeof from 500 to 600 C.

EXAMPLE 5 In this Example, an alloy of titanium and tin is produced froma mixture of SnCl, and TiCL, using sodium as the reducing metal.

In this embodiment, 5 ml. of SnCl, and 95 ml. of TiCl, were placed inthe 500 ml. reactor with grams sodium. The reactor was put in an oilbath which was heated to 160 C. and held at from 140 to 160 C. for 40minutes. The reactor was then shaken end to end in a laboratoryhydrogenation shaker for 20 seconds. It was noticed that immediatelyafter the start of the shaking the residual oil smoked and the bottom ofthe reactor became red hot. After completion of the reaction, 45 gramsof powder and nodules were recovered for a yield of 97 percent. In asubsequent laboratory investigation, the recovered material was found tobe an alloy of percent titanium and 10 percent tin.

The reduction reaction of this Example was initiated at from to C.,whereas the thermal initiation temperature for this reaction lies in therange of from 500 to 600 C.

EXAMPLE 6 In this Example, titanium was produced from titaniumtetrabromide using sodium as the reducing metal.

In this embodiment, 105.4 grams of TiBr, and 28 grams of sodium wereplaced in the 300 ml. reactor and sealed with a copper gasket as well asan eight bolt flange. The sealed reactor was heated in an oil bath at abath temperature in the range of from 208 to 230 C. for a period of 25minutes. The disruption of the reducing metal surface was accomplishedby shaking the reactor in a laboratory shaker for 20 seconds. Uponcompletion of the reaction, 14.0 grams of powder, lumps, and spheruleswere recovered. Since all the sodium was reacted, this was used as abasis for a 100 percent theoretical yield of 14.58 grams of titaniummetal. Accordingly, the actual yield was 96 percent of the theoreticalyield.

The reduction reaction of this Example was initiated at a temperature inthe range of from 208 to 320 C., whereas the thermal initiationtemperature for the reaction lies in the range of from 500 to 600 C.

EXAMPLE7 In this Example, titanium metal was produced from titaniumtetrafluoride using sodium as the reducing metal.

In this embodiment, 108.6 grams of TiF, and 81.6 grams sodium wereplaced in a 300 ml. cylindrical reactor which was sealed with a solidcopper gasket which was, in turn, secured by a bolted blank flange. Thereactor was then placed in an oil bath which was heated in the range offrom 225 to 240 25 C. for 251minutes after which the reactor was shakenfor 60 seconds. 18 seconds after the start of the shaking, the residualoil left on the outside of the reactor began smoking,

thereby indicating that the reaction had been initiated. Upon therealization that only a partial reaction had taken place, the reactorwas again heated in asalt bath at a final temperature of 385 C. Noindication of a further reaction was noted, nor did additional shakinggive any evidence of a further reaction.

After the reactor was opened, the reactor was heatsoaked for 4% hours atfrom 760-790 C. in a crucible furnace. After extensive leaching of theend-product in isopropyl alcohol to kill the residual sodium, followedby a water and a concentrated nitric acid treatment to remove theresidual fluoride, 17.8 grams of powdered and granular titanium wererecovered for a recovery of 42.5 percent of the theoretical amount.

The relatively low recovery is believed to be caused by the lumpy andpowdered nature of the Til starting material which was hydroscopic andwhich possessed an inherently low heat of reaction, certainly lower thanthat for the reduction of the bromide or chloride of titanium.

Nonetheless, titanium was recovered in appreciable amounts from the TiFstarting material in accordance with the procedure of this invention.The reduction reaction of this Example was initiated at from 225 to 240C., whereas the thermal initiation temperature is from 500 to 700 C.

EXAMPLE 8 In this Example, zirconium metal was produced from zirconiumtetrachloride using sodium as the reducing metal.

A large reactor was charged with about 9 kilograms of zirconiumtetrachloride powder before the contents of the reactor were evacuatedthrough an opening therein; such as, for example, a 3/8 inch nipplewelded into the middle of one side of the reactor. A vacuum of 682 mm.(Hg) was maintained over a period of hours during which time argon wasadmitted twice to encourage the removal of HCl and other gases. After afinal addition of argon, the nipple was sealed off and the reactor washeated over a gas flame to a temperature on the top of the reactor ofabout 450 to 470 F. then the reactor was shaken end on end for a periodof 70 seconds. After 40 seconds, the reactor was red over most of itsarea indicating that the reduction reaction was taking place.

After the completion of the reduction reaction, the reactor was openedand the contents thereof examined. The contents consisted of a largeamount of salt (NaCl) substantially free of zirconium metal, and porousfused zirconium metal lying along the side of the reactor. A1- most 70kilograms of salt were segregated. The metal and the remaining saltswere leached with isopropyl alcohol to remove traces of sodium, thensequentially with 0.1 N HCl, IN 11 50,, water and finally methylalcohol. The yield of coarse zirconium metal was 7,569 grams for arecovery of 85 percent while the yield of fine zirconium metal amountedto 1,240 grams or 14 percent, for a total yield of 99 percent of thetheoretical yield.

The reduction reaction of this Example was initiated at about 470 F.,whereas the thermal initiation temperature for this reduction reactionis in the range of from 500 to 600 C.

EXAMPLE 9 In this Example, zirconium metal was produced from zirconiumtetrachloride using a mixture of sodium and calcium as the reducingmetal.

In this embodiment, 55.5 grams (0.238 moles) of zirconium tetrachloridepowder, 12 grams (0.522 moles) of clean sodium and 10 grams (0.250moles) of calcium were placed in a 300 ml. reactor. The reactor wasclosed with a solid copper gasket and an eight bolt blank flange as inExample 1 before the reactor was immersed in a mineral oil bath wherethe oil was held for 25 minutes at from 230 to 235 C. Immediatelythereafter, the reactor was shaken vigorously for 20 seconds resultingin a pronounced smoking of the residual oil on the reactor surface afterabout 6 seconds. This smoking was considered as an indication that anexothermic reaction had been initiated shortly after the start of theagitation.

The resulting reaction mixture was treated with excess isopropyl alcoholto destroy the unreacted sodium and calcium. The alcohol wasincreasingly diluted with water as the hydrogen evolution subsided.After heating the residue on the steam bath for 4 hours withconcentrated HNO the yield was 20.7 grams (95.4 percent recovery) of ablack powder and sponge mixture of zirconium.

The reduction reaction of this Example was initiated in the temperaturerange of from 230 to 235 C., whereas the thermal initiation temperatureis from 500 to 600 C.

EXAMPLE 10 In this Example, vanadium was produced from vanadiumtetrachloride using sodium as the reducing metal.

In this embodiment, 77 ml. of VCl, (containing some VCl contaminant) wasplaced in a 300 ml. reactor with grams of sodium. The reactor wasimmersed in an oil bath which was heated to 145 C. and held in atemperature range of from 140 to 163 C. for 27 minutes. The reactor wasthen shaken for about 23 seconds, during which shaking, smoke becameevident and the bottom of the reactor became red hot. After leaching in1/8N I-lCl overnight, 32.7 grams of vanadium powder and vanadium noduleswere recovered for a yield of 86.7 percent.

The reduction reaction in this Example was initiated in the temperaturerange of from 140 to 163 C., whereas the thermal initiation temperaturefor this reaction is from 500 to 600 C.

EXAMPLE 11 In this Example, niobium was produced from niobiumpentachloride using sodium as the reducing metal.

In this embodiment, grams of NbCl and 41.7 grams of sodium were placedin the 300 ml. reactor and sealed with a solid copper gasket and abolted flange. The reactor was then placed in an oil bath heated in thetemperature range of from 225 to 230 C. for 22 minutes after which thereactor was removed from the bath and shaken for 60 seconds with noevidence of heat development. The reactor was then placed in a salt bathand reheated with the bath temperature rising continuously over a periodof 39 minutes from 229 to 366 C. After the heat treatment in the saltbath, the reactor was shaken in the laboratory shaker for 60 secondsduring which time smoke appeared (at 40 seconds) and the residual oil onthe shaking sleeve caught fire (at 60 seconds). After the completion ofthe reduction reaction, 31.3 grams of fine black niobium powder andsmall niobium metal particles were recovered. The recovery was 91percent of the theoretical value.

In this Example, the reduction reaction was initiated at under 366 C.,whereas the thermal initiation temperature is in the range of from 500to 700 C.

EXAMPLE 12 In this Example, beryllium is produced from BeCl using sodiumas the reducing metal.

In this Example, 50 grams of powdered, anhydrous beryllium chloride and30 grams of sodium were charged to the 300 ml. reactor and the reactorwas heated in an oil bath to a temperature of 230 C. Thereafter, thereactor was shaken for 30 seconds and vigor ous reaction resulted. Uponthe completion of the reaction 2.9 grams of beryllium were recovered fora yield of 52 percent.

This reduction reaction was initiated at 230 C., whereas the estimatedthermal initiation temperature is from 500 to 600 C.

EXAMPLE 13 In this Example, molybdenum was produced from molybdenumsulphide using lithium as the reducing metal.

In this embodiment, a quantity of MoS (natural molybdenite) was groundto 150 mesh and heated under vacuum for several hours. 30.8 grams ofthis treated molybdenite and 8.6 grams of lithium were placed in the 300ml. reactor and heated to an oil bath temperature slightly in excess of230 C. Upon end to end agitation in a laboratory shaker, a moderatereaction occurred. After cooling, 15.6 grams of molybdenum wererecovered for a yield of 85 percent.

This reduction reaction was initiated at about 230 C, whereas thethermal initiation temperature for this reaction is in the range of from500 to 700 C.

The following is a brief discussion of some other exemplary metals whichmay be produced by the procedure of the present invention.

Hafnium can be produced in the same manner as zirconium, see Examples 8and 9 above, by treating hafnium tetrachloride with sodium or a sodiummixture as the reducing metal. The following data taken fromMetallurgical Thermochemistry; Kubaschewski, Evans, and Alcock; PergamonPress; Third Edition (1967), shows the similarities between theimportant properties of zirconium tetrachloride and hafniumtetrachloride essential to the performance of this invention:

l-lfCl ZrCl Boiling Point 316C. (sublimes) 331C. (sublimes) MeltingPoint 437C. 432C. Heat of Formation 236.7 Kcal. 234.7 Kcal.

Uranium can be produced by the reduction of UF with a sodium reducingmetal according to the procedure of this invention, since the heat ofreaction for UF 6Na U 6NalF is l75.8 Kcal. Further, UF melts at 64 C.with a vapor pressure of about 1.5 atmospheres and mixes quickly andcompletely with the reducing metal at low temperatures of about 140 to240 C. Further still, an USAEC Document (ORNL-30l2, C. D. Scott, May 24,1961 clearly shows that UF and sodium react when they are heatedtogether.

Thorium has been produced by the thermally initiated reduction of ThClwith sodium metal at a temperature of about 500 C. according to Z.anorg. allgem. Chem., C. Lely and L. Hamburger at 87,209 (1914).Accordingly, it is evident from the preceding Examples that theprocedure of the present invention can produce thorium at temperaturessignificantly below 500 C.

Reducible metal compounds, other than the reducible metal halides, maybe used as a source of the metal to be recovered, See, for instanceExample 13 abgye in which M05 is reduced by lithium metal according tothe procedure of the present invention. Further, British Pat. Nos.729,503 and 729,504 indicate that TiO Li TiO V 0 Cb O Ta O Cr O M00 W0MnTe, FeS, and U 0 may be reduced to form their respective metals.

Though the present invention has been illustrated above in a number ofspecific examples, the procedure of this invention may obviously beapplied to reducible metal compounds not specifically mentioned above inview of the broader aspects of this procedure.

What is claimed is:

l. A reduction process for the production of metal, which processincludes the steps of a. introducing into a reaction zone withoutpremixing a halide selected from the group consisting of halides oftitanium, zirconium, hafnium, uranium, vanadium, niobium, thorium,beryllium, molybde' num and mixtures thereof and a reducing metalselected from the group consisting of sodium, potassium, calcium,barium, magnesium, lithium and mixtures thereof, said reducible metalcompound and said reducing metal being introduced in amounts providingnot more than l0 percent excess of either reactant over stoichimetricrequirements for complete reduction of the reducible metal halide toreduced metal,

b. sealing the reaction zone,

c. heating the reactants without substantial agitation from atemperature below the melting point of the reducing metal to atemperature which is both above the melting point of the reducing metaland below the temperature at which a reduction reaction between themetal halide and the molten reducing metal will proceed spontaneously,

d. initiating a reduction reaction between the metal halide and themolten reducing metal by suddenly disrupting the surface of the moltenreducing metal by means of a mechanical force sufficient to provide adispersion of the reducing metal in intimate contact with the reduciblemetal compound,

e. permitting the reduction reaction to continue to thereby produce areduced metal in a zero-valence state; and

f. thereafter removing said reduced metal from the reaction zone.

2. The process of claim 1 wherein the reducing metal is an alkali metalselected from the group consisting of sodium, potassium and lithium.

3. The process of claim 1 wherein the reducing metal is selected fromthe group consisting of sodium, potassium, sodium mixed with barium, andsodium mixed with calcium.

4. The process of claim 1 wherein the reducible metal halide is selectedfrom the group consisting of halide of titanium and zirconium.

5. The process of claim 4 wherein the reducing metal is an alkali metalselected from the group consisting of sodium, potassium and lithium.

6. The process of claim 4 wherein the reducing metal is selected fromthe group consisting of sodium, potassium, sodium mixed with barium, andsodium mixed with calcium.

7. The process of claim 6 wherein the reducible metal halide is selectedfrom the group consisting of titanium tetrachloride and zirconiumtetrachloride.

8. A reduction process for the production of metal, which processincludes the steps of a. introducing into a reaction zone withoutpremixing molybdenum sulfide and a reducing metal selected from thegroup consisting of sodium, potassium and lithium and mixtures thereof,said molybdenum sulfide and said reducing metal being introduced inamounts providing not more than 10 percent excess of either reactantover stoichiometric requirements for complete reduction of themolybdenum sulfide to molybdenum metal,

b. sealing the reaction zone,

0. heating the reactants without substantial agitation from atemperature below the melting point of the reducing metal to atemperature which is both above the melting point of the reducing metaland below the temperature at which a reduction reaction between themolybdenum sulfide and the molten reducing metal will proceedspontaneously,

d. initiating a reducing reaction between the molybdenum sulfide and themolten reducing metal by suddenly disrupting the surface of the moltenreducing metal by means of a mechanical force sufficient to provide adispersion of the reducing metal in initmate contact with the molybdenumsulfide,

e. permitting the reduction reaction to continue to thereby producemolybdenum metal,

f. thereafter removing said molybdenum metal from the reduction zone.

9. The process of producing titanium metal which comprises:

a. introducing titanium halide and sodium into a reaction zone withoutpre-mixing and in amounts providing not more than 10 percent excess ofeither reactant over stoichiometric requirements for complete reductionof the titanium halide to titanium metal;

sealing the reaction zone;

. heating the reactants without substantial agitation from a temperaturebelow the melting point of sodium to a temperature which is both abovethe melting point of sodium and below the temperature at which areduction reaction between the titanium halide and molten sodium willproceed spontaneously;

d. initiating a reduction reaction between the titanium halide andmolten sodium by suddenly disrupting the surface of the molten sodium;

e. permitting the reduction reaction to continue to thereby producetitanium metal; and

f. thereafter removing consolidated titanium metal from the reactionzone.

10. The process of claim 9 wherein the titanium halide comprisestitanium tetrachloride and wherein the titanium halide and sodium arepresent in amounts providing not more than 5 percent excess of eitherreactant.

11. The process of claim 9 wherein the titanium halide comprisestitanium tetrachloride and wherein the titanium halide and sodium arepresent in substantially stoichiometric proportions.

12. The process of claim ill wherein the maximum temperature of step (c)is between 120 and 400 C.

13. The process of claim 11 wherein the disruption of step (d) is causedby sudden vertical shaking of the molten sodium.

14. The process of producing zirconium metal which comprises:

a. introducing zirconium halide and sodium or mixtures of sodium andcalcium into a reaction zone without pre-mixing and in amounts providingnot more than 10 percent excess of either reactnat over stoichiometricrequirements for compelte reduction of the zirconium halide to zirconiummetal;

b. sealing the reaction zone;

c. heating the reactants without substantial agitation from atemperature below the melting point of sodium or the mixture of sodiumand calcium to a temperature which is both above the melting point ofsodium or the mixture of sodium and calcium and below the temperature atwhich a reduction reaction between the zirconium halide and moltensodium or mixture of sodium and calcium will proceed spontaneously;

d. initiating a reduction reaction between the zirconium halide andmolten sodium or the mixture of sodium and calcium by suddenlydisrupting the surface of the molten sodium or the mixture of sodium andcalcium;

e. permitting the reduction reaction to continue to thereby producezirconium metal; and

f. thereafter removing consolidated zirconium metal from the reactionzone.

15. The process of claim 9 wherein the zirconium halide compriseszirconium tetrachloride and wherein the zirconium halide and sodium ormixtures of sodium and calcium are present in amounts providing not morethan 5 percent excess of either reactant.

2. The process of claim 1 wherein the reducing metal is an alkali metalselected from the group consisting of sodium, potassium and lithium. 3.The process of claim 1 wherein the reducing metal is selected from thegroup consisting of sodium, potassium, sodium mixed with barium, andsodium mixed with calcium.
 4. The process of claim 1 wherein thereducible metal halide is selected from the group consisting of halideof titanium and zirconium.
 5. The process of claim 4 wherein thereducing metal is an alkali metal selected from the group consisting ofsodium, potassium and lithium.
 6. The process of claim 4 wherein thereducing metal is selected from the group consisting of sodium,potassium, sodium mixed with barium, and sodium mixed with calcium. 7.The process of claim 6 wherein the reducible metal halide is selectedfrom the group consisting of titanium tetrachloride and zirconiumtetrachloride.
 8. A reduction process for the production of metal, whichprocess includes the steps of a. introducing into a reaction zonewithout premixing molybdenum sulfide and a reducing metal selected fromthe group consisting of sodium, potassium and lithium and mixturesthereof, said molybdenum sulfide and said reducing metal beingintroduced in amounts providing not more than 10 percent excess ofeither reactant over stoichiometric requirements for complete reductionof the molybdenum sulfide to molybdenum metal, b. sealing the reactionzone, c. heating the reactants without substantial agitation from atemperature below the melting point of the reducing metal to atemperature which is both above the melting point of the reducing metaland below the temperature at which a reduction reaction between themolybdenum sulfide and the molten reducing metal will proceedspontaneously, d. initiating a reducing reaction between the molybdenumsulfide and the molten reducing metal by suddenly disrupting the surfaceof the molten reducing metal by means of a mechanical force sufficientto provide a dispersion of the reducing metal in initmate contact withthe molybdenum sulfide, e. permitting the reduction reaction to continueto thereby produce molybdenum metal, f. thereafter removing saidmolybdenum metal from the reduction zone.
 9. The process of producingtitanium metal which comprises: a. introducing titanium halide andsodium into a reaction zone without pre-mixing and in amounts providingnot more than 10 percent excess of either reactant over stoichiometricrequirements for complete reduction of the titanium halide to titaniummetal; b. sealing the reaction zone; c. heating the reactants withoutsubstantial agitation from a temperature below the melting point ofsodium to a temperature which is both above the melting point of sodiumand below the temperature at which a reduction reaction between thetitanium halide and molten sodium will proceed spontaneously; D.initiating a reduction reaction between the titanium halide and moltensodium by suddenly disrupting the surface of the molten sodium; e.permitting the reduction reaction to continue to thereby producetitanium metal; and f. thereafter removing consolidated titanium metalfrom the reaction zone.
 10. The process of claim 9 wherein the titaniumhalide comprises titanium tetrachloride and wherein the titanium halideand sodium are present in amounts providing not more than 5 percentexcess of either reactant.
 11. The process of claim 9 wherein thetitanium halide comprises titanium tetrachloride and wherein thetitanium halide and sodium are present in substantially stoichiometricproportions.
 12. The process of claim 11 wherein the maximum temperatureof step (c) is between 120* and 400* C.
 13. The process of claim 11wherein the disruption of step (d) is caused by sudden vertical shakingof the molten sodium.
 14. The process of producing zirconium metal whichcomprises: a. introducing zirconium halide and sodium or mixtures ofsodium and calcium into a reaction zone without pre-mixing and inamounts providing not more than 10 percent excess of either reactnatover stoichiometric requirements for compelte reduction of the zirconiumhalide to zirconium metal; b. sealing the reaction zone; c. heating thereactants without substantial agitation from a temperature below themelting point of sodium or the mixture of sodium and calcium to atemperature which is both above the melting point of sodium or themixture of sodium and calcium and below the temperature at which areduction reaction between the zirconium halide and molten sodium ormixture of sodium and calcium will proceed spontaneously; d. initiatinga reduction reaction between the zirconium halide and molten sodium orthe mixture of sodium and calcium by suddenly disrupting the surface ofthe molten sodium or the mixture of sodium and calcium; e. permittingthe reduction reaction to continue to thereby produce zirconium metal;and f. thereafter removing consolidated zirconium metal from thereaction zone.
 15. The process of claim 9 wherein the zirconium halidecomprises zirconium tetrachloride and wherein the zirconium halide andsodium or mixtures of sodium and calcium are present in amountsproviding not more than 5 percent excess of either reactant.